Profits subject to Petroleum Revenue Tax (PRT) and any associated allowances are assessed for at an individual oil and gas field level. Companies are assessed every six months for each field in which they have an interest.

The number of instances in which companies benefited from oil allowance are shown in the table below for each of the half year periods. A company could be counted more than once in a period if it has interests in multiple fields.

First six months

Second six months

2014-15

26

16

2015-16

12

5

2016-17

Oil allowance did not benefit any company in this year: no PRT was due as the tax was permanently zero-rated from 1 January 2016